What Is Interline? Definition & Meaning in Aviation
An interline agreement lets one airline sell and check baggage on tickets that include another airline’s flights, without the two airlines sharing flight numbers.
In plain language
Interlining makes it possible to buy a single ticket with connections on different airlines and have bags checked through to the final destination.
Example
A journey from Peshawar to Europe on two different airlines may be on one ticket if the airlines have an interline agreement.
Why it matters
Interlining affects what happens when something goes wrong: on a single interline ticket, the airlines are generally expected to look after you if you miss a connection, which is not the case on separate tickets.